Workpiece connector for a power tool

ABSTRACT

A connector ( 20 ) having an assembly ( 28 ) adapted to releasably receive an end ( 33 ) of a workpiece ( 22 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 09/877,717,filed Jun. 8, 2001, now U.S. Pat. No. 6,722,667 which claims the benefitunder 35 U.S.C. §119(e) of Provisional Patent Application No.60/210,631, filed Jun. 9, 2000, the disclosures of which are herebyexpressly incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to power tools and, moreparticularly, to a quick release connector for a handheld power tool.

BACKGROUND OF THE INVENTION

Typical handheld power tools, such as drills, include a chuck adapted tosecurely couple a cylindrical or hex shank of a workpiece, such as adrill bit. In the past, coupling the workpiece to the power tool wasmanually accomplished by inserting the workpiece into the chuck andusing a chuck key to selectively lock the workpiece to the power tool.Developments in coupling the workpiece to the power tool have resultedin a locking mechanism that is actuatable between a locked and unlockedposition with the use of a single hand. Such locking mechanisms lock thehex shank of the workpiece to one side of the connector opposite thelocking mechanism in a pressing operation. Although such lockingmechanisms are effective at coupling a workpiece to a power tool, theyare not without their problems.

One such problem resulting from the existing locking mechanisms resultsfrom how the workpiece is locked to the power tool. In this regard,forcing the hex shank of the workpiece to one side of the connector'shex cavity tends to increase runout in the resulting hex shank/connectorinterface.

Another problem associated with existing locking mechanisms is that thespring mechanism in the connector keeps a substantially constant tensionon the locking mechanism. This tension must be relieved to remove thehex shank from within the connector. As a result, simultaneouslyrelieving the tension and removing the hex shank from the connectorresults in a connector that is difficult to operate with one hand.

Thus, there is a need for a connector for a power tool that is operablewith one hand and reduces potential runout.

SUMMARY OF THE INVENTION

A connector formed in accordance with one embodiment of the presentinvention includes an assembly adapted to releasably receive an end of aworkpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become better understood by reference to the followingdetailed description, when taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of a connector for a power tool formed inaccordance with one embodiment of the present invention;

FIG. 2 is an exploded view of a connector for a power tool formed inaccordance with one embodiment of the present invention;

FIG. 3 is a side exploded view of a connector for a power tool formed inaccordance with one embodiment of the present invention;

FIG. 4 is a cross-sectional view of the connector of FIG. 3 takensubstantially through Section 4—4;

FIG. 5 is a perspective view of an alternate shaft for a connectorformed in accordance with the present invention;

FIG. 6 is a side planar view of the alternate shaft of FIG. 5;

FIG. 7 is an end planar view of the alternate shaft of FIG. 6;

FIG. 8 is an end planar view of the alternate shaft of FIG. 6;

FIG. 9 is a cross-sectional side planar view of the alternate shaft ofFIG. 6; and

FIG. 10 is a cross-sectional side planar view of a connector formed inaccordance with one embodiment of the present invention showingattachment of an optional workpiece attachment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1-4 illustrate a connector 20 formed in accordance with oneembodiment of the present invention. The connector 20 is adapted toselectively attach a workpiece 22 to a power tool (not shown). Althoughthe workpiece 22 is illustrated as a Phillips head screwdriver, otherworkpieces, such as a standard screwdriver and a drill bit, are alsowithin the scope of the present invention.

The connector 20 includes a first collar 24, a spring biased ball pinassembly 26, a shaft assembly 28, and a second collar 30. The workpiece22 is suitably formed from a high strength material and includes acylindrical drive portion of the hex stem 32 and an appropriate shapedhead portion 34. The drive portion of the hex stem 32 is sized to beslidably received within the shaft assembly 28 and is seated therein ona spring biased ball pin assembly 26.

The spring biased ball pin assembly 26 includes a coil spring 36, a ballpin 38, and a plug 40. The spring biased ball pin assembly 26 is biasedto selectively eject the workpiece 22 from within the connector 20, asis described in greater detail below.

The shaft assembly 28 includes a shaft 42, collar springs 44, a ballspring 46, and centering balls 48. One end of the shaft 42 is adapted tobe received within a corresponding chuck of a well known power tool. Theother end of the shaft 42 includes a cavity 50 adapted to lockinglyreceive the hex stem 32 of the workpiece 22. Three of the centeringballs 48 are disposed around the shaft 42 and are received withincorresponding tapered cavities 52. The centering balls 48 are restrainedwithin the cavities 52 by the ball spring 46.

The shaft 42 also includes a pair of tapered cavities 54 aligned along alongitudinal axis extending between the open ends of the shaft 42, suchthat a forward ball 60 is located near the forward or open end of theshaft 42. A rearward ball 62 is located substantially near a midpointdefined along a longitudinal axis extending between the opened andclosed ends of the shaft 42.

Still referring to FIGS. 1-4, operation of the connector 20 will now bedescribed in greater detail. To selectively couple the workpiece 22 tothe connector 20, the drive portion of the hex stem 32 of the shaft 42is inserted into the connector 20, such that the three centering balls48 near the front lift up and over a lower portion 33 of the hex stem 32and drop into a power groove 64. Continued insertion of the shaft 42causes the centering balls 48 to lift up and over the power groove 64and contact the drive portion of the hex stem 32. The lower portion 33of the hex stem 32 eventually contacts the ball pin 38 at the back ofthe shaft's cavity 50. The operator then continues to press theworkpiece 22 into the connector 20. This operation causes the ball pin38, which is tensioned forward by the coil spring 36 to react until thelower portion 33 of the hex stem 32 presses up against the plug 40. Theplug 40 retains the ball pin 38 and allows clearance for a hex pin 37found in other optional hex stem configurations, such as the hex pinfound in a reversible drill and driver manufactured by Jore Corporationand seen in FIG. 10. The ball pin 38 retracts rearwardly to allow therearward ball 62 to drop into its corresponding tapered hole 54 andflush to the diameter of the shaft 42. This, in turn, allows the firstand second collars 24 and 30 to shift forward because it is tensionedtowards the forward position.

In translating forward, the collar forces the forward ball 60 to dropinto its tapered hole 54, thereby locking the hex stem 32 at the powergroove 64. The collar continues forward to contact the three centeringballs 48 located at the front of the connector 20. The internal taper100 (FIG. 4) at the front portion of the first collar 24 forces thethree centering balls 48 to contact the drive portion of the hex stem 32and lock it into a centered position. This locking and centeringoperation takes place by the user simply inserting the workpiece 22 intothe connector 20.

To remove the workpiece 22, the order of operations is basicallyreversed. The operator pulls the collar back. With this operation, thetension is removed from the centering balls 48 and the ball lockingmechanism, comprised of the forward ball 60 and the forward tapered hole54. At the end of its travel, the collar allows space for the rearwardball 62 to move back up out of its hole 54 in the shaft 42. The coilspring 36, inside the connector 20, forces the ball pin 38 forward. Thisin turn forces the rearward ball 62 up and secures the collar in place.The ball pin 38 then moves forward, thus moving the workpiece 22 to aposition where the three centering balls 48, which are tensionedradially inward by the ball spring 46, move off of the drive portion ofthe hex stem 32 and drop back into the power groove 64. The threetensioned balls 48 hold the workpiece 22 at the power groove 64 with alight grip until the operator selectively removes the workpiece 22 fromthe connector 20.

Referring now to FIGS. 5-9, an alternate shaft 142 formed in accordancewith the present invention will now be described in further detail. Theshaft 142 of the alternate embodiment is identical in materials andoperation as the shaft 42 described above with the following exception.As best seen by referring to FIG. 9, the aft hole 154 has been relocatedto a position 180 degrees (based on a longitudinal axis running down thecenter of the shaft 142) from its position shown in the shaft 42 of thefirst embodiment of FIGS. 1-4. With the ball location change of thisalternate embodiment, all of the ball holes are oriented symmetricallyaround the shaft's center axis 160. All other connector components arealso symmetric about the axis 160 when in the assembled position.

The radial balance of this alternate embodiment helps to minimizecentripetal (centrifugal) forces when the connector is rotating in apower drill. Minimizing the forces that result from rotation results inless vibration. This in turn helps utilize the minimized runoutcapabilities of the connector. Less runout from the hex stem component(drill, nut driver, power bit, etc.) results in easier use, and greateraccuracy from the user's standpoint. For the purposes of this invention,radial balance is defined as the center of mass for the assembly as itis aligned with the axis of rotation for the assembly.

While the preferred embodiment of the invention has been illustrated anddescribed, it will be appreciated that various changes can be madetherein without departing from the spirit and scope of the invention.

1. A workpiece connector for a handtool, the workpiece connectorcomprising: (a) a shaft having a longitudinally extending channel, thechannel sized to selectively receive a stem portion of a workpiece; (b)a first collar slidably received on the shaft; (c) a locking assemblyextending between the shaft and the first collar, the locking assemblypositioned to be selectively displaced into locking engagement with agroove formed on the workpiece; and (d) a centering assembly extendingbetween the first collar and the shaft, the centering assemblysimultaneously centering the workpiece within the shaft as the lockingassembly is selectively displaced into locking engagement with theworkpiece, wherein the locking assembly is automatically reciprocatedbetween an unlocked position and a locked position by inserting theworkpiece within the channel.
 2. The workpiece connector of claim 1,wherein the locking assembly comprises at least one ball reciprocallyreceived within a cavity formed in the shaft, the ball being positionedfor selective locking engagement with the groove of the workpiece. 3.The workpiece connector of claim 1, wherein the locking assemblycooperates with sliding motion of the first collar to automaticallyreciprocate the locking assembly between the locked and unlockedpositions.
 4. The workpiece connector of claim 3, further comprising abiased pin assembly disposed within the channel of the shaft, the biasedpin assembly being biased to selectively eject the workpiece from withinthe channel when the locking assembly is displaced into the unlockedposition.
 5. The workpiece connector of claim 1, wherein the centeringassembly includes at least one ball reciprocally mounted within a cavityformed with the shaft and in communication with the channel to engagethe stem portion of the workpiece when the workpiece is received withinthe channel.
 6. The workpiece connector of claim 1, wherein thecentering assembly includes a plurality of balls, each one of theplurality of balls reciprocally disposed within a correspondingly numberof cavities formed with the shaft, the plurality of balls being incommunication with the stem portion of the workpiece when the workpieceis received within the channel to center the workpiece within thechannel.
 7. The workpiece connector of claim 2, further comprising abiased pin assembly disposed within the channel of the shaft, the biasedpin assembly being biased to selectively eject the workpiece from withinthe channel when the locking assembly is displaced into an unlockedposition.
 8. A workpiece connector for a handtool, the workpiececonnector comprising: (a) a shaft having a longitudinally extendingchannel, the channel sized to selectively receive a stem portion of aworkpiece; (b) a collar slidably received on the shaft; (c) means forselectively locking a workpiece within the channel of the shaft, themeans for selectively locking being disposed between the collar and theshaft; and (d) means for centering the workpiece within the shaft, themeans for centering the workpiece being disposed between the collar andthe shaft, wherein the means for selectively locking a workpiece withinthe channel of the shaft is automatically reciprocated between anunlocked position and a locked position by inserting the workpiecewithin the channel.
 9. The workpiece connector of claim 8, wherein themeans for centering the workpiece within the shaft simultaneouslycenters the workpiece within the channel as the means for selectivelylocking a workpiece within the channel of the shaft is displaced intolocking engagement with the workpiece.
 10. The workpiece connector ofclaim 9, wherein the means for selectively locking a workpiece withinthe channel of the shaft comprises at least a first ball received withina cavity formed in the shaft, the at least first ball being positionedfor selective locking engagement with the groove of the workpiece whenthe workpiece is received within the channel.
 11. The workpiececonnector of claim 9, wherein the means for centering the workpiecewithin the shaft comprises a plurality of balls, each one of theplurality of balls being reciprocally disposed within a correspondinglynumber of cavities formed with the shaft, the plurality of balls beingin communication with the stem portion of the workpiece when theworkpiece is received within the channel to center the workpiece withinthe channel.
 12. The workpiece connector of claim 11, further comprisinga biased pin assembly disposed within the channel of the shaft, thebiased pin assembly being biased to selectively eject the workpiece fromwithin the channel when the means for selectively locking a workpiecewithin the channel of the shall is displaced into an unlocked position.13. A workpiece connector for a handtool, the workpiece connectorcomprising: (a) a shaft having a longitudinally extending channel, thechannel sized to selectively receive a stem portion of a workpiece; (b)a first collar slidably received on the shaft; and (c) a centering andlocking assembly disposed between the first collar and shaft, thecentering and locking assembly capable of simultaneously engaging andcentering a workpiece within the longitudinally extending channel of theshaft when the workpiece is received within the longitudinally extendingchannel, wherein the centering and locking assembly is automaticallyreciprocated between an unlocked position and a locked position byinserting the workpiece within the channel.
 14. The workpiece connectorof claim 13, wherein the centering and locking assembly comprises atleast two balls disposed within the shaft, wherein one of the at leasttwo balls centers the workpiece within the channel and the other of theat least two balls lockingly engages the stem of the workpiece when theworkpiece is received within the channel.
 15. The workpiece connector ofclaim 14, further comprising a biased pin assembly disposed within thechannel of the shaft, the biased pin assembly being biased toselectively eject the workpiece from within the channel when thecentering and locking assembly is displaced into an unlocked position.16. A workpiece connector for a handtool, the workpiece connectorcomprising: (a) a shaft having a longitudinally extending channel, thechannel sized to selectively receive a stem portion of a workpiece; (b)a first collar slidably received on the shaft; (c) a first detentassembly extending between the shaft and the first collar, the firstdetent assembly positioned to be selectively displaced into lockingengagement with a groove formed on the workpiece; and (d) a seconddetent assembly extending between the first collar and the shaft, thesecond detent assembly simultaneously centering the workpiece within theshaft as the first detent assembly is selectively displaced into lockingengagement with the workpiece, wherein the first detent assembly isautomatically reciprocated between an unlocked position and a lockedposition by inserting the workpiece within the channel.
 17. Theworkpiece connector of claim 16, further comprising a biased pinassembly disposed within the channel of the shaft, the biased pinassembly being biased to selectively eject the workpiece from within thechannel when the first detent assembly is displaced into the unlockedposition.
 18. The workpiece connector of claim 17, wherein the firstdetent assembly comprises a ball reciprocally received within a cavityformed in the shaft, the ball being positioned for selective lockingengagement with the groove of the workpiece.
 19. The workpiece connectorof claim 18, wherein the second detent assembly includes at least oneball reciprocally mounted within a cavity formed with the shaft and incommunication with the channel to engage the stem portion of theworkpiece when the workpiece is received within the channel.
 20. Theworkpiece connector of claim 18, wherein the second detent assemblyincludes a plurality of balls, each one of the plurality of balls beingreciprocally disposed within a correspondingly number of cavities formedwith the shaft, the plurality of balls being in communication with thestem portion of the workpiece when the workpiece is received within thechannel to center the workpiece within the channel.
 21. The workpiececonnector of claim 20, wherein the plurality of balls are symmetricallyorientated about an axis extending longitudinally through the shaft. 22.The workpiece connector of claim 21, further comprising a biased pinassembly disposed within the channel of the shaft, the biased pinassembly being biased to selectively eject the workpiece from within thechannel when the first detent assembly is displaced into an unlockedposition.
 23. A workpiece connector for a handtool, the workpiececonnector comprising: (a) a shaft having a longitudinally extendingchannel, the channel sized to selectively receive a stem portion of aworkpiece; (b) a collar slidably received on the shaft; (c) a lockingassembly extending between the shaft and the first collar, the lockingassembly positioned to be selectively displaced into locking engagementwith a groove formed on the workpiece, wherein the locking assembly isautomatically reciprocated between an unlocked position and a lockedposition by inserting the workpiece within the channel; and (d) meansfor centering extending between the first collar and the shaft, themeans for centering simultaneously centering the workpiece within theshaft as the locking assembly is selectively displaced into the lockedposition, wherein the locking assembly is displaced locking engagementwith the workpiece.